1. Field of Invention
The present invention relates to a motor detecting and protecting apparatus and its method, and in particular to an apparatus and method capable of determining an instantaneous abnormal state of a motor by utilizing a voltage variation value, an electric current variation value or a rotation speed variation value as reference terms.
2. Related Art
As modern electronic products are rapidly developing along a trend towards higher performance, higher frequency, higher speed and more compactness, heat generated by the electronic products increases. However, electronic products may be unstable at high temperatures, adversely affecting their reliability. Thus, the dissipation of heat has become an important issue for current electronic products, and a fan is normally used as a heat dissipation device for keeping the normal operation of the electronic products.
When a fan or a motor operates, the circuit of the fan or the motor can be impacted by an instantaneous current or voltage that causes the current or voltage to shut down and damages the circuit or the motor of the fan. Also, over-heating can occur because the fan stops operating while the electronic apparatus normally cooled by the fan continues to operate. In order to solve the above-mentioned problems, an over-voltage apparatus or an over-current monitoring apparatus is usually used in a fan to protect the fan from being influenced by instantaneous over-current or instantaneous over-voltage events.
However, the fan using the over-voltage apparatus only can detect an over-voltage condition but cannot immediately detect an instantaneous voltage change and thus cannot effectively protect the fan or the motor. On the other hand, due to the slow response speed of detection, the fan or the motor using the over-current apparatus cannot instantaneously suppress the surge current, which is generated because the voltage changes, and thus the fan or the motor tends to be damaged easily. Therefore, neither the over-voltage apparatus nor the over-current apparatus can immediately detect the instantaneous current variation or instantaneous voltage variation, and thus both of them cannot effectively protect the fan or the motor. This may ultimately shorten the lifetime of the fan or the motor.